Ronstan Single Wire Block, Rivet Eye with 1 3/4" Sheave Dia., 5/32" Max. Wire. Single blocks can double the power of a rope tackle using a cascading block system. Blocks over 1" sheave diameter have removable anodized aluminum sheaves with Delrin bushings. Micro Kite Blocks are very strong, super-lightweight. They are ideal for flag halyards, dinghy outhaul block, cunningham, leech lines and any other small diameter line application.